Manufacture of organic compounds by oxidation.



No. 808,095. PATENTBD DEC. 26, 1905. W. LANG.

MANUFACTURE OF ORGANIC COMPOUNDS BY OXIDATION.

APPLICATION FILED AUG. 28, 1902.

UNITED STATES PATENT OFFICE.

ALTHER LANG, OF SALBKE-ON-THE-ELBE, GERMANY MANUFACTURE OF ORGANIC COMPOUNDS BY OXIDATION.

Specification of Letters Patent.

Patented Dec. 26, 1905.

Application filed August 28, 1902. Serial No. 121,386.

To all whom it may concern:

Be it known that LWVALTHER LANG, doctor of philosophy, a subject of the German Emperor, residing at Salbke-on-the-Elbe, Germany, (whose post-office address is 7 and 8 Wilhelmstrasse, Salbke-on-the -Elbe, Germany,) have invented certain new and useful Improvements in the Manufacture of Organic Uompoundssuch as Aldehydes, Ketones, and Quinonesby Oxidation, (for which I have applied for a patent in Germany on the 2d of August, 1902,) of which the following is a specification.

Among the compounds of manganese only the higher oxids and their salts-such as permanganates, manganates, and the manganic peroxid (also called dioxid )havehitherto been used for the purpose of oxidation, but not the derivatives of manganic oxid (also called sesquioxid or dimanganic trioxid constituted according to the generic formula MnzRs, although it is known through the chemical literature that these compounds also possess oxidizing properties.

The present invention has for its object the application of manganic salts, either alone or in the shape of double salts, for oxidizing purposes, and especially for the production of aldehydes, ketones, and quinones, for which purpose these salts are eminently suitable and yield very good results, while the higher oxide of manganese are frequently quite useless or give only aninferior yield. It is advantageous to work in acid solution. If, for instance, manganic sulfate is employed, the process which takes place in the presence of a body capable of absorbing the oxygen arising from the manganic salt may be represented by the following equation:

The present process derives a special value from the fact, ascertained by experiments, that the manganic salts may be easily and smoothly obtained by the electrolytic oxidation of manganous salts, and that the mixtures of manganous salts and acids may be easily regenerated by this method, so that they only serve as transmitters of the electrolytic oxygen, and that consequently the same acidmanganese mixture may serve for oxidizing an indefinite quantity of hydrocarbons or other suitable organic bodies.

In carrying out this process the substance to be oxidized may be immediately introduced into the electrolyzing vessel, so that the manganic salt formed will immediately yield part of its oxygen to the substance to be oxidized.

For the commercial application of this process some importance must be attributed. to the new and surprising fact that salts of manganic oxid are not subject to reduction at the cathode and that the electrolysis may therefore be performed withoutadiaphragm; nor is it necessary to the success of the electrolysis that the whole of the manganous salt should be dissolved. If the electrolysis is accompanied by mechanical stirring, manganous-oxid salt will be dissolved in proportion as the conversion of manganous salt into manganic salt proceeds until finally the Whole of the manganous salt has been transformed into manganic salt.

In the accompanying drawings, Figure 1 represents a vertical section of an ordinary electrolyzing apparatus which may be used for carrying out my process. Fig. 2 is a horizontal section of the same, and Fig. 3 is a vertical section of a vessel in which the manganic mixture may be caused to act on the material to be oxidized.

The electrolyzing vessel a is made to serve as the anode, while the cathode is formed by a group of rods Zr, arranged in a circle and dipping into the vessel (0, which is provided with a removable cover 5 and a dischargeopening 0. The heads of the rods 7a are joined together by a copper ring L, connected withthe negative-current conductor. In the axis of the vessel (0 is mounted the shaft 2- of an ordinary stirrer set in motion at the top by a pair of bevel-wheels d. The mixing vessel Z (shown in Fig. 3) is provided with a lid m, a discharge-opening n, and astirrer 0. The lid m has a fill-opening 12, provided with a cover 9. A tube a, passing through the lid to the bottom of the mixing vessel, serves to introduce steam after the contents of the vessel have been sufiiciently stirred and caused to react upon each other. The oily mixture passes, with the steam, through an outlet t and discharge-pipe to an ordinary cooler a.

Example: I use as a starting-point the mangano-ammonium sulfate, a salt which has not hitherto been mentioned in technical literature and may be obtained in the shape of yellow anhydrous crystals from a hot acid solution with an excess of ammonium sulfate. Its formula is NIDSO4. 1%(NHQ2SOI, and on the addition of cold water it splits up into MnSOi (NHi)2SOi+aq. and MnSOH-aq. I mix 47.5 kilos of mangano-ammonium sulfate, together with forty-five kilos of water and seventy-nine kilos of ninety-eight per cent. sulfuric acid, in a lead-coated receptacle provided with a stirrer and subject it to electrolysis. The receptacle itself may serve as the anode, and the cathode may likewise consist of lead. The current density on the anode may vary between wide limits. A density of 3.5 amperes per square decinleter has, for instance, given good results. After six thousand ampere hours have been passed through the apparatus the manganese will be present as a manganic-oxid salttl1at is to say, as ammonium-manganese alum, (Mn2(SOi)3(NHi)2SOi,) the greatest part of which is separated out in a state of very fine division. This dark-red salt undergoes decomposition when brought together with water, thereby forming manganic oxid in the shape of brown flakes. After the water evaporated during the electrolysis has been replaced the entire electrolyzing mixture is stirred together with four kilos of toluene in a closed lead-coated receptacle provided with a stirrer. The temperature is maintained at about 50 centigrade. Any appreciable spontaneous heating does not take place, nor is there any pressure developed in the receptacle. During the reaction about eight kilos of water are gradually added. After two to three hours the reaction is completed and the solution and the undissolved salt have become perfectly clear. The oily mixture is driven out with steam and worked up in the known manner. The manganese mixture goes back for repeated electrolysis. From the oily mixture about 0.6 kilo of toluene are recovered and about 3.7 kilos of benzaldehyde are obtained, which is over eighty per cent. of the theoretical quantity in relation to the toluene consumed. No benzoic acid is produced by this method of working, but only small quantities of condensation products in addition to the benzaldehyde. If, however, a considerablyv more diluted acid is employed, benzoic acid will be formed besides the aldehyde. A stronger acid leads to an increased quantity of condensation products, but accelerates the reaction. If the sulfuric acid is considerably stronger than seventy per cent, the electrolytic oxidation does not take place. If it is too dilute, pyrolusite and permanganic acid are produced at the same time. Similar effects are produced if instead of toluene its higher homologues are employed, and many substituted toluenes behave in the same manner. Isoeugenol is oxidized to vanillin.

In case the products of oxidation cannot be driven out with superheated steam they may I be shaken out with a solvent which is insoluble in water.

The new oxidizing agent is capable of extensive application also in the aliphatic series. For instance methyl alcohol is oxidized either to formic aldehyde or to formic acid, according to the accompanying conditions. It is advantageous to work in a closed receptacle. If the threefold quantity of wood-spirit is employed, methylal may be obtained directly. From glycerin glycerin aldehyde is produced.

What I claim is 1. The process for the production of organic compounds obtainable by the oxidation of other organicsubstances, which consists in oxidizing manganous-oxid salts by electrolysis, so as to obtain manganic-oxid salts, and causing the latter to act on the organic substance to be oxidized, substantially as described.

2. The process for the production of organic compounds obtainable by the oxidation of other organic substances, which consists in electrolyzing a mixture of manganousoxid salt and an acid, so as to obtain a manganicoxid salt, causing the latter to act on the organic substance to be oxidized, removing the product of oxidation, and reintroducing the residual manganous-salt and acid mixture into the electrolyzing process, so that a given quantity of manganese compound will serve to oxidize an indefinite quantity of organic substance, substantially as described.

3. The process for the production of an aldehyde by the oxidation of the corresponding hydrocarbon, which consists in oxidizing a manganous-oxid salt by electrolysis, so as to obtain the manganic-oxid salt, and causing the latter to act on the hydrocarbon, substantially as described.

4:. The process for the production of an aldehyde by the oxidation of the corresponding hydrocarbon, which consists in electrolyzing a mixture of a manganous-oxid salt and an acid so as to obtain a manganic-oxid salt, causing the latter to act on the hydrocarbon, removing the aldehyde thus produced and reintroducing the residual manganous-salt and acid mixture into the electrolyzing process, for regenerating the manganic salt and treating with it a fresh quantity of hydrocarbon, substantially a described.

In witness whereof I have hereunto signed my name in the presence of two subscribing witnesses.

VVALTHER LANG.

Witnesses:

FRANZ NIEDERHEITMANN, RUDOLPH FISCHER. I 

